Multi-layered film and the use thereof

The present invention relates to a multi-layered film for the application to a metal or plastic surface, comprising a protective layer (A) as a first layer, which is a poly(alkyl methacrylate) film comprising at least one hindered amine light stabilizer and at least two different ortho-hydroxy tris-aryl triazine UV absorbers as defined below, a barrier layer (B), a base layer (C), an adhesive layer (D) as last layer, and wherein barrier layer (B) and/or base layer (C) comprise at least one pigment, as well as the use of multi-layered films as defined below for the application to the surface of an automobile.

To enhance the visual appearance of such surfaces the use of decorative films has become popular. Spray painting is the traditional method of applying a paint finish. However, spray printing of automobile parts is expensive and is poorly suited for surfacing plastic parts, which have become increasingly popular in the automobile industry. Furthermore, the trend in the automobile industry is away from large volume production of a few models to small volume production of many models, including very short runs of specialty models. Styling differentiation among the numerous models is also desired.

The use of decorative films, especially as a replacement of the traditional lacquers (usually applied by spray printing) can give mono-, multi-color, printing and versatile surface textures and can easily be adapted to varying needs, which may exist for example due to a great number of models, specialty models, or even individual models.

Desirable properties for such films would include high weatherability, high heat resistance, high light stability, high chemical resistance, high solvent resistance, high water resistance and high abrasion resistance. The decorative films should have most of the properties current paintings have. However current decorative films available in the market do not cover all these properties, especially with respect to weatherability. In addition to these properties the decorative films should have enough elongation to cover complex surfaces of automobiles and should be adherent for more than the life time of such automobiles. Furthermore, the films should also have a good flexibility and it should be possible to pigment such films without impairing the other desirable properties of the films. Overall, the durability of the films should be as high as possible.

On the other hand, it is desirable to reduce CO.sub.2 and volatile organic compounds (VOC) emission, which can be achieved by the replacement of traditional lacquers.

Therefore, there is still a need for such films, especially those having improved properties.

The present invention relates to a multi-layered film for the application to a metal or plastic surface, comprising a protective layer (A) as a first layer, which is a poly(alkyl methacrylate) film comprising at least one hindered amine light stabilizer and at least two different ortho-hydroxy tris-aryl triazine UV absorbers selected from the compounds of formulae

and

##STR00001## wherein G.sub.1 is hydrogen, C.sub.1-C.sub.18alkyl, C.sub.1-C.sub.18alkyl substituted by 1, 2 or 3 radicals selected from the group consisting of —OH, C.sub.2-C.sub.18alkenyloxy, —C(O)OL.sub.1 and —OC(O)L.sub.2 with L.sub.1 and L.sub.2 being independently C.sub.1-C.sub.18alkyl; C.sub.3-C.sub.50alkyl interrupted by oxygen or C.sub.3-C.sub.50hydroxyalkyl interrupted by oxygen; G.sub.2, G.sub.3, G.sub.4 and G.sub.5 are independently hydrogen, C.sub.1-C.sub.18alkyl, phenyl or phenyl substituted by 1, 2 or 3 C.sub.1-C.sub.4alkyl;

##STR00002## wherein Q.sub.1, Q.sub.2, Q.sub.3 and Q.sub.4 are independently hydrogen, C.sub.1-C.sub.18alkyl, C.sub.1-C.sub.18alkyl substituted by 1, 2 or 3 radicals selected from the group consisting of —OH, C.sub.2-C.sub.18alkenyloxy, —C(O)OY.sub.1 and —OC(O)Y.sub.2 with Y.sub.1 and Y.sub.2 being independently C.sub.1-C.sub.18alkyl; C.sub.3-C.sub.50alkyl interrupted by oxygen or C.sub.3-C.sub.50hydroxyalkyl interrupted by oxygen, and R.sub.14, R.sub.15 and R.sub.16 are independently from each other hydrogen or C.sub.1-C.sub.18alkyl; a barrier layer (B), a base layer (C), an adhesive layer (D) as last layer, and wherein barrier layer (B) and/or base layer (C) comprise at least one pigment.

Preferred hindered amine light stabilizers are those having a molecular weight of more than 200 g/mol, preferably more than 500 g/mol, especially more than 1,000 g/mol, and more preferably from more than 1,000 up to 100,000 g/mol, e.g. up to 50,000 g/mol. A molecular weight of 1,500 to 15,000 g/mol is especially preferred.

Preference is given to hindered amine light stabilizers, which are compounds of formula

##STR00003## wherein A.sub.1 is hydrogen or C.sub.1-C.sub.4alkyl, A.sub.2 is a direct bond or C.sub.1-C.sub.10alkylene, and n.sub.1 is a number from 2 to 50; or compounds of the formula

##STR00004## in which E.sub.1 is hydrogen, C.sub.1-C.sub.8alkyl, O., —OH, —CH.sub.2CN, C.sub.1-C.sub.18alkoxy, hydroxyl-substituted C.sub.1-C.sub.18alkoxy, C.sub.5-C.sub.12cycloalkoxy, C.sub.3-C.sub.6alkenyl, C.sub.7-C.sub.9phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C.sub.1-C.sub.4alkyl; or C.sub.1-C.sub.8acyl, m.sub.1 is 1, 2 or 4, if m.sub.1 is 1, E.sub.2 is C.sub.1-C.sub.25alkyl, a group of the formula —C(CH.sub.3)═CH.sub.2, or a group of the formula (2a)

##STR00005## in which E.sub.3 is as defined for E.sub.1, if m.sub.1 is 2, E.sub.2 is C.sub.1-C.sub.14alkylene or a group of the formula (2b)

##STR00006## wherein E.sub.4 is C.sub.1-C.sub.10alkyl or C.sub.2-C.sub.10alkenyl, E.sub.5 is C.sub.1-C.sub.10alkylene, and E.sub.6 and E.sub.7 independently of one another are C.sub.1-C.sub.4alkyl, cyclohexyl or methylcyclohexyl, and if m.sub.1 is 4, E.sub.2 is C.sub.4-C.sub.10alkanetetrayl; or compounds of the formula

##STR00007## in which R.sub.1, R.sub.3, R.sub.4 and R.sub.5 independently of one another are hydrogen, C.sub.1-C.sub.12alkyl, C.sub.5-C.sub.12cycloalkyl, C.sub.1-C.sub.4-alkyl-substituted C.sub.5-C.sub.12cycloalkyl, phenyl, phenyl which is substituted by —OH and/or C.sub.1-C.sub.10alkyl; C.sub.7-C.sub.9phenylalkyl, C.sub.7-C.sub.9phenylalkyl which is substituted on the phenyl radical by —OH and/or C.sub.1-C.sub.10alkyl; or a group of the formula (3a)

##STR00008## R.sub.2 is C.sub.2-C.sub.18alkylene, C.sub.5-C.sub.7cycloalkylene or C.sub.1-C.sub.4alkylenedi(C.sub.5-C.sub.7cycloalkylene), or the radicals R.sub.1, R.sub.2 and R.sub.3, together with the nitrogen atoms to which they are bonded, perform a 5- to 10-membered heterocyclic ring, or R.sub.4 and R.sub.5, together with the nitrogen atom to which they are bonded, form a 5- to 10-membered heterocyclic ring, R.sub.6 is hydrogen, C.sub.1-C.sub.8alkyl, O.sup.−, —OH, —CH.sub.2CN, C.sub.1-C.sub.18alkoxy, C.sub.5-C.sub.12cycloalkoxy, C.sub.3-C.sub.6alkenyl, C.sub.7-C.sub.9phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C.sub.1-C.sub.4alkyl; or C.sub.1-C.sub.8acyl, and b.sub.1 is a number from 2 to 50, with the proviso that at least one of the radicals R.sub.1, R.sub.3, R.sub.4 and R.sub.5 is a group of the formula (3a); or compounds of formula (4),

or

##STR00009## wherein R.sub.7 and R.sub.11 independently of one another are hydrogen or C.sub.1-C.sub.12alkyl, R.sub.8, R.sub.9 and R.sub.10 independently of one another are C.sub.2-C.sub.10alkylene, and X.sub.1, X.sub.2, X.sub.3, X.sub.4, X.sub.5, X.sub.6, X.sub.7 and X.sub.8 independently of one another are a group of the formula (4a),

##STR00010## in which R.sub.12 is hydrogen, C.sub.1-C.sub.12alkyl, C.sub.5-C.sub.12cycloalkyl, C.sub.1-C.sub.4alkyl-substituted C.sub.5-C.sub.12cycloalkyl, phenyl, —OH— and/or C.sub.1-C.sub.10alkyl-substituted phenyl, C.sub.7-C.sub.9phenylalkyl, C.sub.7-C.sub.9phenylalkyl which is substituted on the phenyl radical by —OH and/or C.sub.1-C.sub.10alkyl; or a group of the formula (3a) as defined above, and R.sub.13 is hydrogen, C.sub.1-C.sub.8alkyl, O—, —OH, —CH.sub.2CN, C.sub.1-C.sub.18alkoxy, C.sub.5-C.sub.12cycloalkoxy, C.sub.3-C.sub.6alkenyl, C.sub.7-C.sub.9phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C.sub.1-C.sub.4alkyl; or C.sub.1-C.sub.8acyl.

Examples of alkyl having up to 25 carbon atoms are methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, 2-ethylbutyl, n-pentyl, isopentyl, 1-methylpentyl, 1,3-dimethylbutyl, n-hexyl, 1-methylhexyl, n-heptyl, isoheptyl, 1,1,3,3-tetramethylbutyl, 1-methylheptyl, 3-methylheptyl, n-octyl, 2-ethylhexyl, 1,1,3-trimethylhexyl, 1,1,3,3-tetramethylpentyl, nonyl, decyl, undecyl, 1-methylundecyl, dodecyl, 1,1,3,3,5,5-hexamethylhexyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl, octadecyl and eicosyl. One of the preferred definitions of E.sub.1, R.sub.6 and R.sub.13 is C.sub.1-C.sub.4alkyl, especially methyl.

Examples of alkoxy having up to 18 carbon atoms are methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, pentoxy, isopentoxy, hexoxy, heptoxy, octoxy, decyloxy, dodecyloxy, tetradecyloxy, hexadecyloxy and octadecyloxy. One of the preferred meanings of E.sub.1 is octoxy and one of the preferred meanings of R.sub.6 is propoxy.

Examples of C.sub.5-C.sub.12cycloalkyl are cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl and cyclododecyl. C.sub.5-C.sub.8Cycloalkyl, especially cyclohexyl, is preferred.

C.sub.1-C.sub.4Alkyl-substituted C.sub.5-C.sub.12cycloalkyl is for example methylcyclohexyl or dimethylcyclohexyl.

Examples of C.sub.5-C.sub.12cycloalkoxy are cyclopentoxy, cyclohexoxy, cycloheptoxy, cyclooctoxy, cyclodecyloxy and cyclododecyloxy. C.sub.5-C.sub.8Cycloalkoxy, in particular cyclopentoxy and cyclohexoxy, is preferred.

—OH— and/or C.sub.1C.sub.10alkyl-substituted phenyl is for example methylphenyl, dimethylphenyl, trimethylphenyl, tert-butylphenyl or 3,5-di-tert-butyl-4-hydroxyphenyl.

Examples of C.sub.7-C.sub.9phenylalkyl are benzyl and phenylethyl.

C.sub.7-C.sub.9Phenylalkyl which is substituted on the phenyl radical by —OH and/or by alkyl having up to 10 carbon atoms is for example methylbenzyl, dimethylbenzyl, trimethylbenzyl, tert-butylbenzyl or 3,5-di-tert-butyl-4-hydroxybenzyl.

Examples of alkenyl having up to 10 carbon atoms are allyl, 2-methallyl, butenyl, pentenyl and hexenyl. Allyl is preferred. The carbon atom in position 1 is preferably saturated.

Examples of acyl containing not more than 8 carbon atoms are formyl, acetyl, propionyl, butyryl, pentanoyl, hexanoyl, heptanoyl, octanoyl, acryloyl, methacryloyl and benzoyl. C.sub.1-C.sub.8Alkanoyl, C.sub.3-C.sub.8alkenyl and benzoyl are preferred. Acetyl and acryloyl are especially preferred.

Examples of alkylene having up to 18 carbon atoms are methylene, ethylene, propylene, trimethylene, tetramethylene, pentamethylene, 2,2-dimethyltrimethylene, hexamethylene, trimethylhexamethylene, octamethylene and decamethylene.

An example of C.sub.4-C.sub.10alkanetetrayl is 1,2,3,4-butanetetrayl.

An example of C.sub.5-C.sub.7cycloalkylene is cyclohexylene.

An example of C.sub.1-C.sub.4alkylenedi(C.sub.5-C.sub.7cycloalkylene) is methylenedicyclohexylene.

Where the radicals R.sub.1, R.sub.2 and R.sub.3, together with the nitrogen atoms to which they are attached, form a 5- to 10-membered heterocyclic ring, this ring is for example

##str00011##

A 6-membered heterocyclic ring is preferred.

Where the radicals R.sub.4 and R.sub.5, together with the nitrogen atom to which they are attached, form a 5- to 10-membered heterocyclic ring, this ring is for example 1-pyrrolidyl, piperidino, morpholino, 1-piperazinyl, 4-methyl-1-piperazinyl, 1-hexahydroazepinyl, 5,5,7-trimethyl-1-homopiperazinyl or 4,5,5,7-tetramethyl-1-homopiperazinyl. Morpholino is particularly preferred. n.sub.1 is preferably a number from 2 to 25, in particular 2 to 20. b.sub.1 is preferably a number from 2 to 25, in particular 2 to 20.

Preferred as compound of formula

is the compound of formula

##STR00012## wherein n.sub.1 is a number from 2 to 20.

Preferred as compound of formula

are the compounds of formulae

##STR00013## wherein E.sub.1 and E.sub.3 independently of each other are hydrogen, C.sub.1-C.sub.8alkyl, O—, —OH, —CH.sub.2CN, C.sub.1-C.sub.18alkoxy, C.sub.5-C.sub.12cycloalkoxy, C.sub.3-C.sub.6alkenyl, C.sub.7-C.sub.9phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C.sub.1-C.sub.4alkyl; or C.sub.1-C.sub.8acyl.

Further preferred compounds of formula

are those, wherein m.sub.1 is 1, E.sub.1 is C.sub.1-C.sub.18alkoxy or hydroxyl-substituted C.sub.1-C.sub.18alkoxy and E.sub.2 is C.sub.1-C.sub.25alkyl; m.sub.1 is 1, E.sub.1 is hydrogen or methyl and E.sub.2 is a group of the formula —C(CH.sub.3)═CH.sub.2.

Preferred as compound of formula

are the compounds of formulae

##STR00014## wherein b.sub.1 is a number from 2 to 20 and R.sub.6 is hydrogen, C.sub.1-C.sub.8alkyl, O—, —OH, —CH.sub.2CN, C.sub.1-C.sub.18alkoxy, C.sub.5-C.sub.12cycloalkoxy, C.sub.3-C.sub.6alkenyl, C.sub.7-C.sub.9phenylalkyl unsubstituted or substituted on the phenyl by 1, 2 or 3 C.sub.1-C.sub.4alkyl; or C.sub.1-C.sub.8acyl.

Preferred as compound of formula

is the compound of formula

##STR00015## wherein R.sub.17 has one of the meanings of R.sub.6.

Preferred as compounds of formulae

and

are those, wherein R.sub.7 and R.sub.11 are hydrogen, R.sub.8, R.sub.9 and R.sub.10 independently of one another are C.sub.2-C.sub.3alkylene, and X.sub.1, X.sub.2, X.sub.3, X.sub.4, X.sub.5, X.sub.6, X.sub.7 and X.sub.8 independently of one another are a group of the formula (4a), in which R.sub.12 is butyl and R.sub.13 is C.sub.1-C.sub.18alkoxy or C.sub.5-C.sub.12cycloalkoxy.

The meaning of the terminal groups which saturate the free valences in the compounds of formula (1), including those of formula (1-A), and the compounds of formula (3), including those of formulae (3-A), (3-B), (3-C) and (3-D), depend on the processes used for their preparation. The terminal groups can also be modified after their preparation.

If the compounds of the formula

are prepared, for example, by reacting a compound of the formula

##STR00016## in which A.sub.1 is hydrogen or methyl, with a dicarboxylic acid diester of the formula Y—OOC-A.sub.2-COO—Y, in which Y is, for example, methyl, ethyl or propyl, and A.sub.2 is as defined above, the terminal group bonded to the 2,2,6,6-tetramethyl-4-oxypiperidin-1-yl radical is hydrogen or —CO-A.sub.2-COO—Y, and the terminal group bonded to the diacyl radical is —O—Y or

##str00017##

Preferred terminal groups for the compound of formula (1), including those of formula (1-A), are hydrogen and methoxy, ethoxy and propoxy, especially hydrogen and methoxy.

If the compounds of the formula

are prepared by reacting a compound of the formula

##STR00018## in which X is, for example, halogen, in particular chlorine, and R.sub.4 and R.sub.5 are as defined above, with a compound of the formula

##STR00019## in which R.sub.1, R.sub.2 and R.sub.3 are as defined above, the terminal group bonded to the diamino radical is hydrogen or

##STR00020## and the terminal group bonded to the triazine radical is X,

##str00021##

If X is halogen, it is advantageous to replace this, for example, by —OH or an amino group when the reaction is complete. Examples of amino groups which may be mentioned are pyrrolidin-1-yl, morpholino, —NH.sub.2, —N(C.sub.1-C.sub.8)alkyl).sub.2 and —NR(C.sub.1-C.sub.8alkyl), in which R is hydrogen or a group of the formula (3a).

This applies likewise to the compounds of formulae (3-A), (3-B), (3-C) and (3-D).

The compounds of the formula

also cover compounds of the formula

##STR00022## wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5 and b.sub.1 are as defined above and R.sub.4* has one of the meanings of R.sub.4 and R.sub.5* has one of the meanings of R.sub.5.

The hindered amine light stabilizer of formula

is more preferably TINUVIN® 622.

The hindered amine light stabilizer of formula

is more preferably TINUVIN® 123, TINUVIN® 144, TINUVIN® 765, TINUVIN® 770, ADK STAB® LA-81, 82 or 87.

The hindered amine light stabilizer of formula

is more preferably TINUVIN® NOR 371, CHIMASSORB® 944 or CHIMASSORB® 2020, especially TINUVIN® NOR 371.

The hindered amine light stabilizer of formula

is more preferably CHIMASSORB® 119.

The hindered amine light stabilizers of formulae

and

are more preferably FLAMESTAB® NOR 116.

Especially preferred as hindered amine light stabilizers are those of formulae (1), (2), (3), (4),

and (6), more preferably those of formulae (2),

and (4), and especially those of formula (3). As to each of these formulae the definitions and preferences given above apply.

The activity of such hindered amine light stabilizers, especially those of the NOR type, is not influenced by the external environment like acid rain and internal environment like desorption of chloride from polyvinylidene chloride. Furthermore, such hindered amine light stabilizers can provide heat stability to the films for the life time of automobiles.

Examples of C.sub.1-C.sub.18alkyl in formulae

and

are methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, 2-ethylbutyl, n-pentyl, isopentyl, 1-methylpentyl, 1,3-dimethylbutyl, n-hexyl, 1-methylhexyl, n-heptyl, isoheptyl, 1,1,3,3-tetramethylbutyl, 1-methylheptyl, 3-methylheptyl, n-octyl, 2-ethylhexyl, 1,1,3-trimethylhexyl, 1,1,3,3-tetramethylpentyl, nonyl, decyl, undecyl, 1-methylundecyl, dodecyl, 1,1,3,3,5,5-hexamethylhexyl, tridecyl, tetradecyl, pentadecyl, hexadecyl, heptadecyl and octadecyl. C.sub.1-C.sub.8alkyl, for example methyl, n-butyl, tert.-butyl, n-hexyl, 2-ethylhexyl or an isomeric mixture of octyl, is particularly preferred.

Preferred examples of C.sub.1-C.sub.18alkyl, preferably C.sub.2-0.sub.18 alkyl, substituted by 1, 2 or 3 radicals selected from the group consisting of —OH, C.sub.2-C.sub.18alkenyloxy, —C(O)OL.sub.1 (or —C(O)OY.sub.1) and —OC(O)L.sub.2 (or —OC(O)Y.sub.2) in formulae

and

are 2-hydroxyethyl,

##str00023##

An example of C.sub.3-C.sub.50alkyl interrupted by one or more oxygen is —(CH.sub.2CH.sub.2—O—).sub.3—CH.sub.3.

Preferred examples of C.sub.3-C.sub.50hydroxyalkyl interrupted by oxygen in formulae

and

are

##str00024##

A preferred example of phenyl substituted by 1, 2 or 3 C.sub.1-C.sub.4alkyl in formula

is 2,4-dimethylphenyl.

The compound of the formula

is preferably a compound of the formula

##str00025## ##str00026##

More preferably, the compound of formula

is a compound of formulae (7-A) to (7-D), especially a compound of formula (7-C).

Interesting commercially available compounds of formula

are TINUVIN® 479, TINUVIN® 1600, TINUVIN® 1577 and ADK STAB® LA-46.

The compound of the formula

is preferably a compound of the formula

##STR00027## especially a compound of formula (8-B).

An interesting commercially available compound of formula

is TINUVIN® 460.

A further interesting commercially available UV absorber is ADK STAB® LA-1000.

It is preferred that the protective layer (A) comprises at least one ortho-hydroxy tris-aryl triazine UV absorber of formula

and at least one ortho-hydroxy tris-aryl triazine UV absorber of formula (8), whereby the above definitions and preferences apply.

An ortho-hydroxy tris-aryl triazine UV absorber of formula

absorbs at relatively longer wavelength of ultraviolet, whereas the absorption of other components of the films, like polyvinylidene chloride, polyurethane and some pigments, are weak at such wavelengths.

The compounds of formulae

to

described above are essentially known and commercially available, and can be prepared according to known processes.

As pigments, conventional inorganic or organic pigments can be used, like those given in “Gächter/Müller: Plastics Additives Handbook, 3rd Edition, Hanser Publishers, Munich Vienna N.Y.”, pages 647 to 659, point 11. 2. 1. 1 to 11. 2. 4. 2.

Examples of inorganic pigments are titanium dioxide, zinc oxide, carbon black, cadmium sulfide, cadmium selenide, chromium oxide, iron oxide, lead oxide, bismuth vanadate and mixed metal oxides like Ni/Sb/Ti oxide, Cr/Sb/Ti oxide, Mn/Sb/Ti oxide, Sn/Zn/Ti oxide, Zn/Fe oxide, Fe/Cr oxide, Co/Al oxide, Co/Al/Cr oxide, Co/Ti/Ni/Zn oxide, Co/Cr/Fe/Mn oxide, pearl, metallic pigments etc.

Examples of organic pigments are azo pigments, especially disazo pigments, anthraquinones, phthalocyanines, tetrachloroisoindolinones, quinacridones, isoindolines, quinophthalones, pteridines, perylenes, pyrrolopyrroles, liquid crystal pigments etc.

Barrier layer (B) and/or base layer (C) comprise at least one pigment, being preferred that each of barrier layer (B) and base layer (C) comprises at least one pigment.

Poly(alkyl methacrylates) of protective layer (A) are preferably homo-, co- or terpolymers, especially homo- or copolymers, and preferably contain C.sub.1-C.sub.10-alkyl esters of methacrylic acid or acrylic acid as the monomer unit, or mixtures thereof. C.sub.1-C.sub.4-alkyl esters of methacrylic acid are preferred. Methyl methacrylate is particularly preferred, and is preferably employed in amounts of from 50 to 100 weight-%, especially 80 to 100 weight-% of the above monomer mixtures. The co- and/or termonomer, if any, is preferably chosen from alkyl esters of acrylic acid; C.sub.1-C.sub.8-alkyl esters of acrylic acid are preferred, which are preferably employed in amounts of from 0 to 50 weight-%, especially 0 to 20 weight-% of the above monomer mixtures. Examples of such C.sub.1-C.sub.8-alkyl esters of acrylic acid are methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, pentyl acrylate, hexyl acrylate, octyl acrylate and 2-ethylhexyl acrylate. Particularly preferred are poly(methyl methacrylates), especially those with a methyl methacrylate monomer content of 80 to 100 weight-%, preferably 90 to 100 weight-%, and optionally 0 to 20 weight-%, preferably 0 to 10 weight-% of C.sub.1-C.sub.8-alkyl esters of acrylic acid. In addition to the poly(alkyl methacrylates), protective layer (A) can contain a diene-based polymer. Such diene-based polymers are preferably those comprising 20 to 100 weight-% of 1,3-butadiene monomer units and 0 to 80 weight-% of other monomer units, especially those comprising 30 to 100 weight-% of 1,3-butadiene monomer units and 0 to 70 weight-% of other monomer units, and most preferably those comprising 50 to 100 weight-% of 1,3-butadiene monomer units and 0 to 50 weight-% of other monomer units. Examples of such other monomer units are styrene and derivatives thereof, like styrene, alpha-methylstyrene and p-methylstyrene; aromatic vinyl compounds, like vinyltoluene; C.sub.1-C.sub.8-alkyl esters of acrylic acid like methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethylhexyl acrylate; C.sub.1-C.sub.8-alkyl esters of methacrylic acid like methyl methacrylate and ethyl methacrylate.

Protective layer (A) comprises preferably 0 to 50 weight-%, especially 1 to 50% and more preferably 5 to 50 weight-% of diene based polymers, based on the weight of protective layer (A).

Protective layer (A) is preferably transparent and is used to protect the other layers, especially against environmental conditions, like the deleterious effect of sunlight. Protective layer (A) is preferably present in the form of a film, especially a film having a thickness of 10 to 200 μm, preferably 20 to 200 μm and more preferably 20 to 100 μm.

The protective layer (A) contains the hindered amine light stabilizer(s) preferably in an amount of 0.005 to 5 weight-%, in particular 0.01 to 1 weight-% and especially 0.01 to 1 weight-%, relative to the weight of the protective layer (A).

In addition, protective layer (A) contains the ortho-hydroxy tris-aryl triazine UV absorbers preferably in an amount of 0.01 to 15 weight-%, in particular 0.1 to 10 weight-% and especially 0.1 to 5 weight-%, relative to the weight of the protective layer (A).

The barrier layer (B) is preferably used to reduce gas and moisture permeability, and is preferably a polyvinylidene chloride film, a cyclo olefin copolymer, polyethylenenaphthalate film or polyethylene or polypropylene film, especially a polyethylene or polypropylene film. According to a further embodiment of the present invention a polyvinylidene chloride film, a cyclo olefin copolymer or a polyethylenenaphthalate film are preferred.

Barrier layer (B) is preferably present in the form of a film, especially a film having a thickness of 10 to 200 μm, preferably 20 to 200 μm and more preferably 20 to 100 μm.

The barrier layer (B) may contain pigments and, if so, preferably in an amount of 0.5 to 20 weight-%, in particular 1 to 20 weight-% and especially 1 to 15 weight-%, relative to the weight of the barrier layer (B). Furthermore, it is also possible that complex designs are printed on barrier layer (B).

Furthermore, barrier layer (B) may also contain at least one hindered amine light stabilizer. If used, these are preferably present in barrier layer (B) in an amount of 0.005 to 5 weight-%, in particular 0.01 to 1 weight-% and especially 0.01 to 1 weight-%, relative to the weight of the barrier layer (B).

Base layer (C) is preferably a thermoplastic polyurethane resin. Base layer (C) is preferably present in the form of a film, especially a film having a thickness of 10 to 400 μm, preferably 20 to 200 μm and more preferably 100 to 200 μm.

Examples of polyurethane resins include resins obtained by carrying out a polymerization addition reaction between polyhydroxy compounds and polyisocyanate compounds. Here, specific examples of polyhydroxy compounds include: polyester polyols containing products of condensation reactions between phthalic acid, isophthalic acid, adipic acid, maleic acid, and other polybasic acids and ethylene glycol, propylene glycol, butylene glycol, diethylene glycol, trimethylol propane, glycerol, pentaerythritol, and other polyhydroxy compounds; polycaprolactone and other lactone-based polyester polyols; polyhexylene carbonate diol, polynonylene carbonate diol, polycyclohexylene carbonate diol, polydimethylcyclohexyl carbonate diol, and other polycarbonate polyols; and polyoxypropylene glycol, polyoxyethylene polyoxypropylene glycol, polyoxytetramethylene glycol, and other polyether polyols. Acrylic polyols, castor oil derivatives, and the like, are furthermore included. Moreover, ethylene glycol, propylene glycol, butanediol, neopentyl glycol, cyclohexane dimethanol, and other hydroxy compounds, and dimethylolpropionic acid, dimethylolbutanoic acid, and other carboxyl group-containing hydroxy compounds also are included. Examples of polyisocyanate compounds include toluene diisocyanate, diphenylmethane diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, and bis(methylisocyanate) cyclohexane.

The base layer (C) may contain pigments and, if so, preferably in an amount of 0.5 to 20 weight-%, in particular 1 to 20 weight-% and especially 1 to 15 weight-%, relative to the weight of the base layer (C). Furthermore, it is also possible that complex designs are printed on base layer (C).

Furthermore, base layer (C) may also contain at least one hindered amine light stabilizer. If used, these are preferably present in base layer (C) in an amount of 0.005 to 5 weight-%, in particular 0.01 to 1 weight-% and especially 0.01 to 1 weight-%, relative to the weight of the base layer (C).

According to a preferred embodiment barrier layer (B) and/or base layer (C) comprise at least one plasticizer. Such plasticizer can be used to improve elongation of the films, especially for the application of the films to complex shapes of surfaces.

Suitable plasticizers include, but are not limited to, phthalate esters, as well as adipates, azelates, phosphates, and epoxidized oil. A commonly used plasticizer is di(2-ethylhexyl) phthalate (DOP). Other useful plasticizers include tricresyl phosphate, dibutyl phthalate, dibutyl sebacate, tributyl phosphate, epoxidized esters, dioctyl phthalate, trioctyl phosphate, dioctyl sebacate and adipate, and various low-molecular weight polymers such as polypropylene glycol esters. Furthermore, oligomer type plasticizer, like Joncryl ADP1200, and polybutylacrylate polymers can be used.

It is preferred that plasticizers are used for base layer (C) and optionally for barrier layer (B).

The adhesive layer (D) can be any solvent or water based, hot melt, or extruded adhesive. The adhesive layer may for example be selected from polyurethane or polyacrylic adhesives, or polyisobutene. Polyurethane and polyisobutene, especially polyurethane, are preferred. Examples of polyurethane adhesives are Dispercoll® U (available from Bayer MaterialScience AG) as well as polyurethane adhesive as described in WO-A-2012/065966.

The adhesive layer (D) is preferably applied to base layer (C) by coating, and is preferably present in the form of a film, especially a film having a thickness of 1 to 100 μm, preferably 1 to 50 μm and more preferably 5 to 40 μm.

The multi-layered film according to the present invention may be prepared by laminating layers (A), (B) and (C), and then coating of base layer (C) with the adhesive layer (D).

Lamination may be carried out according to conventional methods, where the individual layers are combined with one another by vacuum deposition, lamination, extrusion lamination (adhesive lamination, melt lamination, or hotmelt lamination). It is preferred to carry out lamination by adhesive lamination, like wet or dry lamination (it being possible to use the adhesives given above for adhesive layer (D)).

The adhesive layer (D) can be applied, for example, by means of roll-application processes in the lamination process, or by means of a die in the extrusion lamination process.

If desired, each of layers (A) to (D) may further contain one or more conventional additives. Suitable examples are listed in the following.

1. Antioxidants

The description continues in the full USPTO document.